Static elimination system



J. SLEPIAN STATIC BLIIINATION SYSTBI Filed NOV. 16 1921 Race/Per l l 24 8 l8 I9 23 INVENTOR Jg seph Slap/2m 7 ATTORNEY WITNE SS I W is Z Patented Oct. 28, 1924.

UNITED STATES PATENT. OFFICE.

JOSEPH SLEPIAN, OF SWISSVALE, PENNSYLVANIA, ASSIGNOR T0 WESTINGHOUSE ELECTRIC & MANUFACTURING COMIANY, A CORPORATION OF PENNSYLVANIA.

STATIC ELIMINATION SYSTEM.

Application filed November 16, 1921. Serial No. 515,581.

To all whom it mag concern:

Be it known that I, JosErH SLEPIAN, a citizen of the United States, and a resident of Swissvale, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Static Elimination Systems, of which the following is a specification.

My invention relates to wireless receiving systems and more especially to tuning means particularly adapted for minimizing the effects of static disturbance-s.

In its broad aspect, the object of my invention is to provide a wireless receiving system embodying highly efficient means for eliminating disturbances tending to cause interference.

Another object of my invention is to'provide a receiving system having such characteristics as to be selectively responsive to received signal impulses of predetermined frequency only.

A still further object of my invention is to providea: receiving qstem wherein such voltage-dropsas are given by currents of value i may be balanced by" voltages ob tained by taking the double integral of said currents with respect to time.

Heretofore, various systems have been proposed embodying resonant-circuit arrangements tending to reduce interference between stations and to eliminate the undesirable effect of static impulses. However, such systems have proved only partially successful in that the resonant circuits embodied in such systems have a tendency to be set in oscillation by shock excitation, despite the utilization of various shielding schemes.

According to my invention, I provide means adapted to be utilized in any of the well known receiving systems, whereby the above mentioned defects may be minimized orentirely removed. The desired result may be obtained by including,-in a local receiving conductor, a resistor having such value as to effectively damp the receiving system. Non-resonant means are then associated with said resistor, whereby the voltage-drop therein may be substantially neutralized for currents of predetermined frequency only, as explained more fully hereinafter.

pulse.

These and other objects and applications of my invention, whereby my invention may be practiced, will be apparent from the foli lowing description and claims when read in connection with the accompanying drawing, wherein The single figure is a diagrammatic representation of a wireless receiving system embodying my invention.

In the drawing, an antenna 1 is connected to a ground conductor 2, through a tuning coil 3, a resistor 4 and a capacitive reactance device or condenser 5. Wave responsive apparatus 6, of well known form, may be opera-tively coupled to the antenna circuit through a coupling coil 7 and the tuning coil 3. The resistance of the resistor 4 is sufficient to rapidly damp disturbing electromotive forces having steep wave fronts, such, for example, as are found in a static km The impedance of the condenser 5 is relatively small in comparison with that of the resistor 4.

A three-electrode tube 8 is shown as comprising an anode 9, a grid 11 and a hot cathode 12. The hot cathode 12 may be energized by means of a source of directcurrent energy 13 through a resistor 14. A grid circuit for the tube 8 includes a primary winding 15 of a coupling transformer 16. A secondary winding 17 of the transformer 16 is connected around the resistor 4. The transformer 16 is so designed as to have a high self-inductance to received signal impulses.

A plate-filament circuit for the tube 8 comprises a source of direct-current energy 18, a resistor 19, a capacitive reactance del vice or condenser 21 and a radio-frequency choke coil 22 which is connected in shunt to said condenser. The internal impedance of the tube 8 is regarded as being embodied in the resistor 19.

A second three-electrode tube 22 is shown pulses, the potent al-drop across the'resistor 4 is impressed upon the input electrodes 11 and 12 of the tube 8, thereby causing cur:

rents of value 1', to traverse the plate-filament circuit of the tube 8. These currents are determined by the relation I i J t where pi, is the voltage factor ofthe tube 8, R is the resistance of resistor 4t, 2' is the current through the resistor 4 and R is the resistance of the resistor 19.. The capacitance of condenser 21 is so chosen that the currents in the plate filan'ient circuit of the tube 8 are practically determined by the resistance of resistor 19. 'Therefoie, the reactance of the condenser 21 need not considered in the aboveequation.

The voltage-drop 6 across the condenser 21 is determined by the relation vvhere C is the capacitance of the condenser 21.

The voltage 6 is applied to the grid of the tube 22, thereby causing a voltage drop c s he onden er 5 hich is ve y the relation ffidtdtegsinpi Substituting this value in theequation for a, t sf wid tha B' The evcralconstantsmaybe 5Q dj t d thatthe voltagedrop, across the condenser 5 isequaLand opposite to that across the resistor 4. Hence, the voltage drop-in the circuit between points 33.. and

or across the resistor 4 and condenser 5, W111 be zero, and We have the equat1on:

In vieW of the foregoing, it may readily be seen that, when the constants of the tube circuits are so adjusted that M: 2 a c one, P

the voltagewdrqp across the condenser 5 just balances the voltage drop across the resistor i, thus nullifying the. impedance of the resistor 4 to the currents havin the desired frequency. For currents of ot erfrequencies, the resistor 4 becomes effective to damp out the disturbing impulses.

An advantage of my invention is the provision of a static elimination system having no resonant elements, such as would be setin oscillation by static impulses.

While I have, shown only one embodiment of my v ntion n. the ppended, d ng, it is capable of various modifications and changes Without departing from the spirit fmy in ent n. d I i h e re, tha only such limitations shall be imposed thereon as are demanded, by the prior art or by the appended claims.

, I claim as my invention:

1. In an electrical system, a circuit carry ing currents, an impedance device and a capacitive reactance, device in series circuit relation thereto and means responsive. to the p tentiahdr p acro s said imp dan device for impressing such modified currents across said, capacitive device that the vvol .flgtl' ps acrosssaid de ices nullify one another.

2. In an, electrical system, a circuit carrying periodically varyingcurrents, a resistor device and a capacitive-reactanoe deviceineluded inseriescircuit relation thereto, said resi tor-hav ng a r t ly igh mpedan e in comparison with said react-ance device, and means responsive to the potential-drop across said, resistor for impressirw amplified currents acrosssaid capacitive device, said las rmention d cur n s h ng u hc arcc: teristics as to cause the voltages across said dev s t b an 8. In a Wireless receiving system, a re ceiving circuit. including a resistor and a capa'citi e rc cta 'e evice, sa esistor having such resiste fifi isto efieewel reen the sys em from st t c distur ances,

and" means e c ively sponsive to" currents Qi' prede e m ned requ ncy n said, erm -v ingrci c t-a whereby t vo tag f rop across sa d re s or may e lanc y an OPPOT site vcltagedrcv a ss a d apaciti e reactance device.

. 4.. In an electrical system, a circuit carry: ingi currents of predetermined frequency and pparatus-associa ed herewith-1591 tively responsive to currents of said freuency, said apparatus comprising a high resistance resistor and a relatively lowimpedance capacitive reactor serially included in said circuit, and means associated with said resistor and with said reactor for causing the potential drops across said resistor and reactor to be balanced for currents of said predetermined frequency only.

5. In an electrical system, a pair of threeelectrode tubes having input and output circuits, the output circuit of one tube being interlinked with the input circuit of the remaining tube, a high-impedance element included in the input circuit of said firstmentioned tube, a relatively low-impedance element included in the output circuit of said second-mentioned tube and a work circuit including said impedance elements in series relation, the constants of said input and output circuits being such that, for currents of predetermined frequency in said work circuit, the voltage-drop across said high-impedance element caused by said currents is balanced by an opposite voltagedrop across said low-impedance element.

6. In an electrical system, a pair of threeelect-rode tubes having aperiodic input and output circuits, the output circuit of one tube being electro-statically interlinked with the input circuit of the remaining tube, a high-impedance resistor element included in the input circuit of said first-mentioned tube, a relatively low-impedance capacitive reactance element included in the output circuit of said second mentioned. tube and a work circuit serially including said elements, the constants of said input and out put circuits being such that, for currents of predetermined frequency in said work circuit, the voltage-drop across said resistor caused by said currents is balanced by an opposite voltage-drop across said capacitive element.

7. In a wireless receiving system, a pair of three-electrode tubes having aperiodic input and output circuits, the output circuit of one tube being electro-statically interlinked with the input circuit of the remain ing tube, a resistor included in the input circuit of said first-mentioned tube, a capacitive reactance device included in the output circuit of said second-mentioned tube, said device having a low-impedance relative to that of said resistor, and areceiving con ductor serially including said resistor and said device, the constants of said input and output circuits being such that, for cur rents of predetermined frequency in said receiving conductor, the voltage-drop across said resistor caused by said currents is balanced by an opposite voltage-drop across said capacitive device, and said resistor having such resistance as to effectively damp the receiving conductor with respect to ourrents differing from said currents of predetermined frequency. v p

8, In an electrical system, a three-electrode tube having plate-filament and gi'idfilament circuits, said latter circuit including a resistor of value R, said former circuit having a resistance ofvalue R, and in cluding a capacitive reactance device of value (1,, a second threeelectrode tube having plate-filament and grid-filament circuits, said latter grid-filament circuit including said capacitive reactance device, said latter plate-filament circuit having a resistance of value R and including a capacitive reactance device of value (1,, and a circuit serially including said resistor and said last-mentioned reactance device, the constants being adapted. to be so adjusted that the potentialdrops across said resistor and said device are substantially balanced when currents of substantially the form 2': a sin pt traverse said latter circuit.

9. In a wireless receiving system, a receiving conductor adapted to carry currents of substantially the form 2': A sin pt and including a resistor of value R and a ca pacitive reactance device of value G a three-electrode tube having a voltage factor 1., operatively associated with said resistor and responsive to the potential drop thereacross upon the receipt of impulses, a platefilament circuit for said tube having a resistance of value R and a capacitive reactance device of value G a second three-electrode tube having a voltage factor 1. operatively associated with said plate-filament circuit and responsive to potential variations across said last-mentioned reactance device, a plate-filament circuit for said sec- 0nd tube including a resistance of value and said capacitive reactance device of value 10. The method of tuning which consists in balancing potentials of value f(a:) against potentials of value A f f f (w) dxdac, where f is a given function of a given variable quantity m, proportional to time, and A is a constant.

11. The method of tuning which consists in balancing voltages given by currents of value 2' against voltages obtained by taking the double integral of said currents with respect to time.

12. In connection with a wireless receiving system including a. receiving conductor having a resistance of such value as to effectively screen the system from static disturbances, the method of producing, in said conductor, a negative-resistance reaction of such value as to compensate for losses 125 caused by currents of predetermined frequency in said resistance which consists in impressing upon said conductor voltages obtained by taking the double integral of said currents with respect to time.

13. The combination with a circuit adapttially neutralize the voltage-drop across said .ed to be energized from a desired source of resistor with respect to desired currents but 10 ,periodio voltages of a given frequency and not with respect to undesired currents.

also from an undesired source of volta 'es of In testimony whereof, I have hereunto difi'erent nature, of a series-connected dampsubscribed my name this 31st day of Cote ing resistor and non-resonant current-re ber, 1921 sponsive means for impressing on said circuit a voltage of such nature as to substan- JOSEPH SLEPIANf 

